1. Field of the Invention
The present invention relates to a resist composition suitable for lithography and the like, acting by radiation ray of high energy such as far ultraviolet ray (including excimer laser and the like), electron beam, X ray or radiation light and the like.
2. Description of Related Art
Recently, with progress in higher integration of integrated circuits, there occurs a requirement for formation of submicron patterns. Particularly, lithography using excimer laser from krypton fluoride or argon fluoride is paid to attention since it enables production of 64 M DRAM to 1 G DRAM. As the resist suitable for such an excimer laser lithography process, there is a tendency to adoption of a so-called chemical amplification type resist utilizing chemical amplification effect. In the case of the chemical amplification type resist, an acid generated from an acid generating agent at parts irradiated with radiation diffuses by the subsequent heat treatment (post exposure bake: hereinafter, abbreviated as PEB), and solubility of the irradiated parts in an alkali developer is changed in a reaction using this acid as a catalyst, and by this, positive patterns are provided.
A chemical amplification type positive resist is characterized by containing of a resin insoluble or poorly soluble itself in an alkali aqueous solution but becoming soluble in an alkali aqueous solution by the action of an acid, and an acid generating agent. When a resin has an adamantane skeleton, the resin is expensive though it is excellent particularly in resolution.
An object of the present invention is to provide a chemical amplification type positive resist composition giving lowered cost without decreasing basic abilities such as sensitivity, resolution and the like.
The present inventors have intensively studied for attaining such an object and resultantly found that cost can be reduced steeply without significantly deteriorating basic abilities of a resist, by mixing a resin insoluble or poorly soluble itself in an alkali aqueous solution but becoming soluble in an alkali aqueous solution after dissociation of a protective group having a specific adamantine skeleton by the action of an acid, a resin obtained by protecting a part of hydroxyl groups in cheap poly(p-hydroxystyrene) by a protective group not dissociating by the action of an acid or a resin obtained by substituting a part of hydroxyl groups in cheap poly(p-hydroxystyrene) by hydrogen, as resin components of a chemical amplification type positive resist, leading to completion of the present invention.